F650gs starting issue

At the battery idle I get 12.1v, 4000 rpm 12.4v. The rectifier is putting out around 15.1v.

The picture is the rectifier I removed
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Rectifier is putting out 15.2 volt. But at the battery only showing 12.4 max
Turn engine off. At battery 12.5v. pull plugs off rectifier. Showing the same.
What am I missing

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So the problem remains. Strange - initially this had all the hallmarks of a bike that had been jump started from a running car, but not in your ownership we understand, so we have to look at the RR/wiring loom & battery.

I attach an install walk through, for fitting a MOSFET to a Honda (couldn't find a BMW installation).

http://www.speedzilla.com/forums/ho...ngen-fh012aa-regulator-rectifier-install.html

You say the OE BMW plugs have been removed, so presumably the wires from the MOSFET have been spliced into the loom - surely this is where the problem lies? Solder joints can crack up, crimps corrode - somehow you have a significant voltage drop between RR & battery. Then the RR output is over spec (should be c14.5V) suggesting that is failing . Also, if under/overcharging has been going on, the battery condition always becomes questionable - can you beg/borrow a known good battery from a buddy?

Finally, I do not know how the canbus may try to interfere with the output - you would need expert opinion there. However, there is the option to take the DC output direct to the battery as explained in the link.

Perhaps you can post some pics of the connectors & how they are spliced into the loom. Also a pic of the back of the MOSFET RR, the side that is hidden when mounted - is it clean, or showing any signs of overheating. Does it show the RR spec?

Good luck sorting the issue .............. KEN
 
The rectifier is new. It is giving up to 14.5v I think I misread the first reading.

Oddly if I measure the voltage at the battery and then measure at the rectifier plug, I get the same. But once the bike starts the rectifier voltage doesn't reach the battery.

Going to throw it into a skip at this rate

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No news as such. Weather is hindering checking. I did notice one day, the bike is fitted with a 3 led battery minitor thingy, that it flashed green whilst running for about 50 meters. No joy since

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No news as such. Weather is hindering checking. I did notice one day, the bike is fitted with a 3 led battery minitor thingy, that it flashed green whilst running for about 50 meters. No joy since

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Probably best to remove that, in case it's failing & bleeding volts. Same with any Aux electrical equipment - after market lights/grips/satnav cradle - best disconnected until you sort this out.
 
Probably best to remove that, in case it's failing & bleeding volts. Same with any Aux electrical equipment - after market lights/grips/satnav cradle - best disconnected until you sort this out.
I believe the issue is the battery. Extensive tests on the wiring system has revealed no issues. But as soon as I plug the rectifier in, the voltage seems to drop. Pass through tests reveal no shorts or anything.

When the new battery arrives, I will leave everything disconnected. And after charging it, will see what happens.

I charged the old battery last night. Only lasts less than an hour on a ride. That's with no heated grips, not using indicators or brakes where safe to. I know the headlight stays on but 2 weeks ago, I did a 3 hour round trip that the battery coped with.

Of course I could be Barking up the wrong tree

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OK as a finalish update.

Battery changed and no change. So ran a wire direct from the rectifier to the battery and guess what, no change.

Without wiring rectifier is throwing out 14.2v plugging into the wiring it doesn't charge the bike.

Why do I say finalish. Because I am unemployed, waiting for total knee replacement on both knees, and suffered a heart attack last year so I cannot afford to do more.

So going to sell and walk away

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Sorry to hear that.

Something, somewhere is bleeding away charging output, a parasitic drain. It's just a case of tracking down the culprit - sounds simple; always frustrating. Usually due to retro-fit accessories, hence my suggestion to disconnect anything & everything that is not OE BMW. The usual culprits are Satnav cradles, alarms, aux lights & heated grips. Shame you can't track it down. Still, could be anywhere, given the electrics had already received attention from a previous owner (stator/mosfet RR/battery monitor).

Anyway, good luck with the knee replacements ............. & the bike sale idc. All the best .............. KEN
 
I had the battery direct to the bike, no externals plugged in. Just the bike. That's what confused me as I also had wondered it is was the Sat nav or something else added.

And I had expected or hoped that bypassing the bike wiring, that the voltage would be there.

I wonder is the stator fubar but I have no way to take it out and test

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